Incidence and persistence of asymptomatic Leishmania infection among HIV-infected patients in Trang province, Southern Thailand: A cohort study.

Leishmaniasis poses a significant health burden, particularly among immunocompromised patients. In Thailand, Leishmania infection caused by Leishmania martiniquensis and Leishmania orientalis lacks information about the incidence and risk factors among HIV-infected populations. This longitudinal cohort study aimed to investigate the incidence and persistence of Leishmania infection among HIV-infected individuals in an affected area, Trang Province, Southern Thailand. The study also identified risk factors associated with the incidence of Leishmania infection. The study enrolled 373 participants in the HIV clinic, Trang Hospital, who initially tested negative for Leishmania infection during 2015-2016, and 133 individuals initially tested positive for Leishmania infection. Thus, follow-up visits of 506 participants occurred during 2018-2019. Direct Agglutination Test (DAT) and nested PCR (nPCR) identified incidents and persistent cases of Leishmania infection. Cox proportional-hazards regression analyses were performed to assess risk factors for the incidence of Leishmania infection. Among the initially negative group, 12 incident cases comprised one L. orientalis infection and 11 seropositive cases using DAT, resulting in a cumulative incidence of 3.2% and an incidence density of 10.38 per 1000 person-years. Increasing age was a significant predictor of the incidence of Leishmania infection. Five persistent cases comprised one Leishmania donovani complex and four seropositive cases using DAT in the initially positive group, with a cumulative persistence rate of 3.7% and a persistence density of 12.85 per 1000 person-years. All patients were asymptomatic. This study sheds light on the incidence and persistence of Leishmania infection among HIV-infected individuals in Trang Province, Southern Thailand, underscoring the importance of continued monitoring and tailored interventions to mitigate the impact of this co-infection.

Asymptomatic Leishmania Infection among Blood Donors in a Southern Province of Thailand.

Leishmaniasis poses significant public health challenges in endemic regions. Understanding the prevalence of asymptomatic Leishmania infection and identifying risk factors among blood donors is crucial. This study addressed a knowledge gap by evaluating the prevalence of asymptomatic Leishmania infection and pinpointing associated risk factors among blood donors in an endemic area in Thailand and aimed to enhance blood donation safety protocols and reduce the risk of transfusion-transmitted Leishmania infection. A cross-sectional study and a longitudinal follow-up were conducted among 500 blood donors in Trang Province, southern Thailand. A serological test was performed using the direct agglutination test (DAT), and DNA detection was performed using nested polymerase chain reaction (nPCR) to screen for Leishmania infection. Potential risk factors associated with the infection were also assessed. The study identified a 19.0% prevalence of asymptomatic Leishmania infection among blood donors, with nPCR proving more effective in detecting infections (13.0%) than DAT (6.4%). Notably, Leishmania martiniquensis was the predominant species identified, highlighting the local epidemiological profile of Leishmania infection. Furthermore, using multivariate analysis, living in stilt houses was independently associated with Leishmania infection (adjusted odds ratio = 1.85; 95% CI = 1.04-3.28; P = 0.035). A high prevalence of asymptomatic Leishmania infection among blood donors underscores the need for integrating comprehensive Leishmania screening protocols into blood donation processes, particularly in endemic regions. It advocates for using molecular diagnostics to enhance detection accuracy. Furthermore, living in stilt houses as a risk factor emphasizes the importance of environmental management in leishmaniasis control efforts.

Risk Factors of Leishmania Infection among HIV-Infected Patients in Trang Province, Southern Thailand: A Study on Three Prevalent Species.

There are two main species of Leishmania reported in Thailand, that is, Leishmania siamensis and Leishmania martiniquensis. Moreover, leishmaniasis cases caused by Leishmania donovani complex were also reported. There is still a lack of information concerning risk factors of Leishmania infection in Thailand. This study aimed to identify the risk factors of Leishmania infection caused by these three species among HIV-infected patients. A cross-sectional study was conducted in HIV clinic at Trang Hospital, Thailand. Nested PCR and sequencing were performed to detect Leishmania DNA in blood and saliva samples and identify Leishmania species. A standardized questionnaire was used to interview individuals. A total of 526 patients were recruited in this study. Sixty-three (12.0%) were positive for L. siamensis, 24 (4.6%) were positive for L. martiniquensis, and 23 (4.4%) were positive for L. donovani complex. Risk factors of L. siamensis infection included using intravenous drug (adjusted odds ratio [AOR] 2.01, 95% CI: 1.01-4.02). Risk factors of L. martiniquensis infection included female gender (AOR 4.23, 95% CI: 1.52-11.75), using recreational drug (AOR 3.43, 95% CI: 1.00-11.74), and having comorbidities (AOR 4.94, 95% CI: 2.00-12.21). Risk factors of L. donovani complex infection included having opportunistic infection (AOR 4.22, 95% CI: 1.00-17.79), CD4 count 200-500 cells/mm3 (AOR 3.64, 95% CI: 1.14-6.86), and not using insect repellent (AOR 3.04, 95% CI: 1.08-8.58). This study identified the risk factors of Leishmania infection caused by three Leishmania species in Thailand. The data could be useful for disease prevention and control. Further studies on trends of Leishmania infection and preventive measures are recommended.

Detection of Leishmania DNA in saliva among patients with HIV/AIDS in Trang Province, southern Thailand.

Leishmaniasis is a neglected tropical disease causing opportunistic infection among patients with HIV/AIDS. The fatal form of this disease is visceral leishmaniasis (VL). DNA of Leishmania can be detected in saliva, for which the collection is noninvasive and requires little expertise. This study aimed to evaluate the sensitivity and specificity of a nested-PCR to amplify the Internal Transcribed Spacer 1 (ITS1) to detect Leishmania DNA in paired saliva and buffy coat samples of 305 Thai patients with HIV/AIDS in Trang Hospital, Trang Province, southern Thailand. For asymptomatic Leishmania infection among Thai patients with HIV/AIDS, the sensitivity and specificity of the nested-PCR-ITS1 in buffy coat were 73.9 and 100%, respectively. However, the sensitivity in saliva was 26.1% and specificity was 100%. Using the nested-PCR-ITS1, saliva and buffy coat samples showed positive agreement in only 52.0% of patients. Saliva tested results with the nested-PCR-ITS1 showed positive agreement with the Direct Agglutination Test (DAT) in 46.5% of patients. Only 12.1% of the samples showed positive agreement for Leishmania infection among all the three tests: saliva, buffy coat and DAT results. Using nucleotide sequencing, at least three species of Leishmania infection were identified in saliva, i.e., L. siamensis (n = 28), L. martiniquensis (n = 9), and L. donovani complex (n = 1). As a result, buffy coat still appears to be a better specimen to diagnose asymptomatic VL infection among individuals with HIV. However, the use of both buffy coat and saliva together as clinical specimens would increase the sensitivity of Leishmania detection.

Prevalence and risk factors associated with Leishmania infection in Trang Province, southern Thailand.

BACKGROUND: Autochthonous cutaneous and visceral leishmaniasis (VL) caused by Leishmania martiniquensis and Leishmania siamensis have been considered emerging infectious diseases in Thailand. The disease burden is significantly underestimated, especially the prevalence of Leishmania infection among HIV-positive patients. METHODS: A cross-sectional study was conducted to determine the prevalence and risk factors associated with Leishmania infection among patients with HIV/AIDS living in Trang province, southern Thailand, between 2015 and 2016. Antibodies against Leishmania infection were assayed using the direct agglutination test (DAT). DNA of Leishmania was detected by ITS1-PCR using the buffy coat. Species of Leishmania were also identified. RESULTS: Of 724 participants, the prevalence of Leishmania infection was 25.1% (182/724) using either DAT or PCR assays. Seroprevalence of Leishmania infection was 18.5% (134/724), while Leishmania DNA detected by the PCR method was 8.4% (61/724). Of these, 24.9% (180/724) were asymptomatic, whereas 0.3% (2/724) were symptomatic VL and VL/CL (cutaneous leishmaniasis). At least five species were identified: L. siamensis, L. martiniquensis, L. donovani complex, L. lainsoni, and L. major. Multivariate analysis showed that CD4+ levels <500 cells/µL and living in stilt houses were independently associated with Leishmania infection. Those who were PCR positive for Leishmania DNA were significantly associated with a detectable viral load, whereas non-injection drug use (NIDU) and CD4+ levels <500 cells/µL were potential risk factors of Leishmania seropositivity. CONCLUSIONS: A magnitude of the prevalence of underreporting Leishmania infection among Thai patients with HIV was revealed in this study. Effective public health policy to prevent and control disease transmission is urgently needed.

Leishmaniasis in Thailand: A Review of Causative Agents and Situations.

Before 1999, leishmaniasis was considered an imported disease in Thailand. Since then, autochthonous leishmaniasis was reported in both immmunocompetent and immmunocompromised patients especially in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). A new species was identified and named as Leishmania siamensis consisting of two lineages, that is, lineages TR and PG. Analysis of isoenzymes has clarified the more commonly detected L. siamensis lineage PG as Leishmania martiniquensis (MON-229), a species originally reported from the Martinique Island, whereas the L. siamensis lineage TR has been identified as the true novel species, L. siamensis (MON-324). Both cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) have been found among Thai patients. Disseminated CL and VL could be presented in some reported patients who had HIV/AIDS coinfection. So far, only sporadic cases have been reported; thus, the true prevalence of leishmaniasis should be determined in Thailand among the high-risk populations such as people with HIV/AIDS. A recent survey among animals identified L. martiniquensis DNA in black rats (Rattus rattus) suggesting a potential animal reservoir. In addition, L. martiniquensis DNA was identified in Sergentomyia gemmea and Sergentomyia barraudi, the predominant sandfly species in the affected areas. However, further studies are needed to prove that these sandflies could serve as the vector of leishmaniasis in Thailand.

Autochthonous disseminated dermal and visceral leishmaniasis in an AIDS patient, southern Thailand, caused by Leishmania siamensis.

We report the first establishment of in vitro cultivation and genotypic characterization of Leishmania siamensis isolated from an autochthonous disseminated dermal and visceral leishmaniasis in a Thai acquired immunodeficiency syndrome (AIDS) patient. The molecular identification has shown that the parasite was identical to L. siamensis, a recently described Leishmania species reported in the southern provinces of Thailand. The phylogenetic analysis has confirmed L. siamensis as closely related to the zoonotic Leishmania species L. enrietti.